Retro Savage Sadists (1980)

Two vicious thugs break into a woman's house and fuck her. It turns out said woman is married to a low-rent pornographer who owes a mobster money. When the woman goes to her husband's office to tell him what happened to her, the thugs follow her to the office and proceed to not only fuck her again, but also fuck both the husband's secretary and another hapless lass who just happens to be in the wrong place at the wrong time.